A nano-sustained release pharmaceutical fertilizer with a polydopamine coating and its preparation method

Abstract

The present invention belongs to the technical field of slow-release medicine fertilizers, and particularly relates to a nano-slow-release medicine fertilizer with a polydopamine coating and a preparation method thereof. The nano-slow-release medicine fertilizer adopts a simple one-pot method, and through the coordination assembly between zinc ions and imidazole-2-carboxaldehyde, a fungicide and a fertilizer are encapsulated in the synthesized zinc-based nano-carrier ZIF-90, and finally a layer of polydopamine is coated outside the carrier. The nano-slow-release medicine fertilizer comprises the following components by mass percentage: 45-60 wt% of zinc-based nano-carrier ZIF-90, 15-30 wt% of medicine fertilizer, and 5-15 wt% of coating material polydopamine. The nano-slow-release medicine fertilizer prepared and disclosed by the present invention has the characteristics of small average particle size, good biocompatibility, and environmental safety, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of slow-release pharmaceutical fertilizers, and particularly relates to a nano slow-release pharmaceutical fertilizer with a polydopamine coating and a preparation method thereof. Background Art

[0002] Fertilizers refer to a class of chemical substances that can supply nutrients required for the growth and development of crops, improve the soil properties, and increase the yield and quality of crops. Pesticides refer to chemical preparations used for preventing and controlling crop pests and diseases, regulating plant growth, and increasing the yield and quality of crops. However, the loss of a large amount of fertilizers and pesticides not only causes economic losses, but also may cause serious pollution of water bodies, soil and air, thereby threatening human health.

[0003] To solve this problem, the development of slow-release pharmaceutical fertilizers is particularly crucial. Compared with traditional slow-release pesticides or fertilizers, slow-release pharmaceutical fertilizers can not only provide the nutrients required for the normal growth of crops, but also effectively kill pests, germs and harmful animals and plants, thereby ensuring the healthy growth of crops and then increasing the overall agricultural yield. In addition, slow-release pharmaceutical fertilizers can also improve the utilization rates of pesticides and fertilizers at the same time, reducing the waste caused by overuse. More importantly, it can avoid the residues of pesticides and fertilizers in the soil due to excessive concentration, thereby preventing soil pollution and ensuring the sustainable use of the soil.

[0004] At present, most of the slow-release pharmaceutical fertilizers on the market exist in the form of pharmaceutical fertilizer granules. These pharmaceutical fertilizer granules are usually prepared in the following ways: First, an inert porous material (such as zeolite) can be used as a physical carrier, and the role of this carrier is to fix pesticides and fertilizers in its internal porous structure; Second, chemical fertilizer granules can be used as carriers, and then pesticides are loaded on them and a coating process is carried out; Third, pesticides and fertilizers can be directly coated; Finally, pesticide active ingredient granules, compound fertilizer granules and fillers are mixed and then directly coated to prepare slow-release pharmaceutical fertilizers. However, most of these slow-release pharmaceutical fertilizers are prepared from non-degradable, toxic and non-environmentally friendly raw materials. Therefore, there is an urgent need to develop a degradable, non-toxic and environmentally friendly slow-release fertilizer. Summary of the Invention

[0005] In view of this, to solve this problem, the purpose of the present invention is to provide a nano slow-release pharmaceutical fertilizer with a polydopamine coating and a preparation method thereof. The nano slow-release pharmaceutical fertilizer is a slow-release pharmaceutical fertilizer with a zinc-based metal-organic framework as a carrier, good biocompatibility, environmental protection and degradability, and longer drug efficacy and fertilizer efficiency time.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The first technical objective of the present invention is to provide a nano-sustained release medicated fertilizer with a polydopamine coating. The nano-sustained release medicated fertilizer uses ZIF-90 as a carrier, with the medicated fertilizer wrapped inside the carrier and polydopamine coated on the outside of the carrier. Moreover, the nano-sustained release medicated fertilizer, by mass percentage, comprises the following components:

[0008] 45-60 wt% zinc-based nano-carrier ZIF-90, 15-30 wt% medicated fertilizer, and 5-15 wt% polydopamine.

[0009] It should be noted that dopamine is an endogenous nitrogen-containing organic compound that can polymerize to form polydopamine. The synthesis schematic diagram is as follows:

[0010]

[0011] Polydopamine has strong adhesion and chemical activity and can react with various functional groups. Although there have been studies developing medicated fertilizer products with good sustained release effects, these products often need to use polymer materials as templates and then attach polydopamine to their surfaces, which undoubtedly poses higher requirements for the safety of medicated fertilizer raw materials. ZIF-90, as a kind of metal-organic framework material (MOFs), is composed of zinc ions and imidazole-2-carboxaldehyde and has characteristics such as good biocompatibility, high loading efficiency, excellent sustained and controlled release performance, and large specific surface area. As a medicated fertilizer delivery carrier, ZIF-90 shows great application potential.

[0012] Optionally, the medicated fertilizer is composed of a bactericide and a fertilizer in a mass ratio of 5:3; the bactericide is one or a combination of more than one of fludioxonil, tebuconazole, and difenoconazole, and the fertilizer is one or a combination of more than one of urea, ammonium bicarbonate, potassium chloride, ammonium chloride, nitrophosphate potassium fertilizer, superphosphate, and ammonium phosphate.

[0013] Optionally, the polydopamine is composed of dihydroxyindole, indolinedione, and dopamine basic units.

[0014] The second technical objective of the present invention is to provide a preparation method of the nano-sustained release medicated fertilizer with a polydopamine coating as described above.

[0015] The preparation method of the nano-sustained release medicated fertilizer with a polydopamine coating specifically comprises the following steps:

[0016] 1) The zinc-based nano-carrier ZIF-90 wrapped with the medicated fertilizer is prepared by a simple one-pot method:

[0017] Take a certain amount of zinc acetate and the medicine-fertilizer and add them to an N,N-dimethylformamide solution to obtain solution A; dissolve an appropriate amount of imidazole-2-carboxaldehyde in the N,N-dimethylformamide solution to obtain solution B; under stirring conditions, add solution B to solution A, react for a period of time, centrifuge to collect the obtained mixture, and wash it three times with methanol, and finally dry to obtain a zinc-based nanocarrier ZIF-90 with the medicine-fertilizer encapsulated inside.

[0018] 2) Coating the outside of the carrier with polydopamine is synthesized by using a coupling agent through the cross-linking reaction of carboxyl and amino groups:

[0019] Disperse the zinc-based nanocarrier ZIF-90 with the medicine-fertilizer encapsulated inside prepared in step 1) in water, add hydrogen peroxide, react at room temperature for 1 hour, centrifuge and wash with water to obtain a carboxylated zinc-based nanocarrier ZIF-90 with the medicine-fertilizer encapsulated; add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to the aqueous solution of the carboxylated zinc-based nanocarrier ZIF-90 with the medicine-fertilizer encapsulated (solution C), activate for 1 hour, and then add an aqueous solution of hydrochloric acid dopamine containing N-hydroxysuccinimide (solution D) to solution C, and the mixed solution reacts under stirring for 24 hours; finally, obtain the nanosustained-release medicine-fertilizer with the polydopamine coating by centrifuging, washing and drying.

[0020] Optionally, in step 1), the ratio of the added zinc acetate to imidazole-2-carboxaldehyde is 2:3 (w / w); the volume ratio of solution A to B is 1:1.

[0021] Further, the reaction system conditions in step 1) are 25 °C, a rotation speed of 300 rpm, and an addition speed of 4 mL / min. Optionally, in step 2), the molar concentration of hydrogen peroxide is 20.5 mmol / L, the mass ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to N-hydroxysuccinimide is 5:3, and the mass ratio of dopamine to the carboxylated zinc-based nanocarrier ZIF-90 with the medicine-fertilizer encapsulated is 1:4.

[0022] Further, in step 2), the volume ratio of solution C to D is 5:3.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1) The present invention has developed a nanosustained-release medicine-fertilizer with a polydopamine coating. The nanosustained-release medicine-fertilizer uses ZIF-90 as the carrier, with the medicine-fertilizer encapsulated inside the carrier and polydopamine coated on the outside of the carrier. Encapsulating the medicine-fertilizer in the zinc-based nanocarrier ZIF-90 prolongs the time of the medicine effect and the fertilizer effect, avoids the waste of fertilizers and pesticides, improves their utilization efficiency, and has an intelligent controlled-release effect.

[0025] 2) The zinc-based nanocarrier ZIF-90 is used as the main material of the nano-controlled-release fertilizer and medicine in the present invention. It has good biocompatibility and can provide the essential micronutrient zinc and the important nutrient element nitrogen for plant growth and development, improve soil fertility, and promote plant growth.

[0026] 3) The present invention uses polydopamine as a multifunctional coating, which can improve the utilization efficiency of fertilizers, reduce the impact on the environment, and contribute to the sustainable development of modern agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0028] Figure 1 It is the SEM image of the zinc-based nanocarrier ZIF-90 prepared by the present invention;

[0029] Figure 2 It is the SEM image of the zinc-based nanocarrier ZIF-90 after polydopamine coating. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] The special term "embodiment" used here does not necessarily mean better or superior to other embodiments as illustrated by "exemplary". For the performance index tests in the embodiments of this application, unless otherwise specified, the conventional test methods in the art are used. It should be understood that the terms described in this application are only for describing specific embodiments and are not used to limit the content disclosed in this application.

[0032] Unless otherwise specified, the technical and scientific terms used in this article have the same meanings as those commonly understood by those of ordinary skill in the technical field to which this application belongs; the test methods and technical means not specifically noted in this application are all the experimental methods and technical means commonly used by those of ordinary skill in the art.

[0033] To better illustrate the content of this application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that this application can still be implemented without certain specific details. In the embodiments, some methods, means, instruments, devices, etc. well-known to those skilled in the art are not described in detail in order to highlight the gist of this application.

[0034] On the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the obtained technical solutions belong to the content disclosed in the embodiments of this application.

[0035] The present invention discloses a nano-sustained release pharmaceutical fertilizer with a polydopamine coating and a preparation method thereof.

[0036] To better understand the present invention, the following embodiments are used to further specifically elaborate on the present invention, but it should not be understood as a limitation to the present invention. For those skilled in the art, some non-essential improvements and adjustments made according to the above-mentioned invention content are also considered to fall within the protection scope of the present invention.

[0037] Example 1

[0038] (1) Take 0.2 g of zinc acetate, 0.5 g of fludioxonil, and 0.3 g of urea and add them to 20 mL of N,N-dimethylformamide solution, and ultrasonically dissolve them for 5 minutes to obtain solution A; dissolve 0.3 g of imidazole-2-carboxaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; under the conditions of 25 °C, 300 rpm, and 4 mL / min, add solution B to solution A, and continue to stir for 30 minutes after adding. Centrifuge to collect the obtained mixture, and wash it three times with methanol, and finally dry to obtain a zinc-based nanocarrier encapsulating the pharmaceutical fertilizer, labeled as LJ-ZIF-90.

[0039] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water, and add the hydrogen peroxide solution thereto under magnetic stirring, react for 24 hours, centrifuge to collect the product, and wash it with water, and finally dry to obtain carboxylated LJ-ZIF-90;

[0040] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; under the condition of stirring at 400 rpm, add solution D to solution C, centrifuge to collect the precipitate after reacting for 24 hours, and wash it with water, and finally dry to obtain the nano-sustained release pharmaceutical fertilizer with a polydopamine coating.

[0041] Example 2

[0042] (1) Take 0.2 g of zinc acetate, 0.5 g of fludioxonil, 0.1 g of urea and 0.2 g of ammonium phosphate and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to dissolve them fully to obtain solution A; dissolve 0.3 g of imidazole-2-carboxaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 25 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry it to obtain a zinc-based nanocarrier with internal drug-fertilizer encapsulation, labeled as LJ-ZIF-90.

[0043] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Add the hydrogen peroxide solution thereto under magnetic stirring conditions and react for 24 hours. Centrifuge to collect the product and wash it with water. Finally, dry it to obtain carboxylated LJ-ZIF-90;

[0044] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; add solution D to solution C under the condition of stirring at 400 rpm. After reacting for 24 hours, centrifuge to collect the precipitate and wash it with water. Finally, dry it to obtain a nano-sustained release drug-fertilizer with a polydopamine coating.

[0045] Example 3

[0046] (1) Take 0.2 g of zinc acetate, 0.5 g of tebuconazole, 0.15 g of urea and 0.15 g of potassium chloride and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to dissolve them fully to obtain solution A; dissolve 0.3 g of imidazole-2-carboxaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 25 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry it to obtain a zinc-based nanocarrier with internal drug-fertilizer encapsulation, labeled as LJ-ZIF-90.

[0047] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Under magnetic stirring, add the hydrogen peroxide solution thereto and react for 24 hours. Centrifuge to collect the product, wash it with water, and finally dry it to obtain carboxylated LJ-ZIF-90;

[0048] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; under stirring at 400 rpm, add solution D to solution C, react for 24 hours, then centrifuge to collect the precipitate, wash it with water, and finally dry it to obtain a nano-sustained release fertilizer and pesticide with a polydopamine coating.

[0049] Example 4

[0050] (1) Take 0.2 g of zinc acetate, 0.5 g of tebuconazole, and 0.3 g of potassium chloride and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonicate for 5 minutes to fully dissolve them to obtain solution A; dissolve 0.3 g of imidazole-2-carbaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; under the conditions of 25 °C, 300 rpm, and 4 mL / min, add solution B to solution A. After adding, continue stirring for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry it to obtain a zinc-based nanocarrier encapsulating fertilizer and pesticide, labeled as LJ-ZIF-90.

[0051] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Under magnetic stirring, add the hydrogen peroxide solution thereto and react for 24 hours. Centrifuge to collect the product, wash it with water, and finally dry it to obtain carboxylated LJ-ZIF-90;

[0052] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; under stirring at 400 rpm, add solution D to solution C, react for 24 hours, then centrifuge to collect the precipitate, wash it with water, and finally dry it to obtain a nano-sustained release fertilizer and pesticide with a polydopamine coating.

[0053] Example 5

[0054] (1) Take 0.2 g of zinc acetate, 0.5 g of difenoconazole, 0.2 g of urea and 0.1 g of superphosphate and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to fully dissolve them to obtain solution A; dissolve 0.3 g of imidazole-2-carboxaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 25 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry to obtain a zinc-based nanocarrier with internal encapsulated medicine and fertilizer, labeled as LJ-ZIF-90.

[0055] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Add the hydrogen peroxide solution thereto under magnetic stirring and react for 24 hours. Centrifuge to collect the product and wash it with water. Finally, dry to obtain carboxylated LJ-ZIF-90;

[0056] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; add solution D to solution C under stirring at 400 rpm and react for 24 hours. Then centrifuge to collect the precipitate and wash it with water. Finally, dry to obtain a nano-sustained release medicine and fertilizer with a polydopamine coating.

[0057] Example 6

[0058] (1) Take 0.2 g of zinc acetate, 0.5 g of difenoconazole, 0.3 g of superphosphate and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to fully dissolve them to obtain solution A; dissolve 0.3 g of imidazole-2-carboxaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 25 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry to obtain a zinc-based nanocarrier with internal encapsulated medicine and fertilizer, labeled as LJ-ZIF-90.

[0059] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Under magnetic stirring, add the hydrogen peroxide solution thereto and react for 24 hours. Centrifuge to collect the product, wash it with water, and finally dry it to obtain carboxylated LJ-ZIF-90;

[0060] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; under the condition of stirring at 400 rpm, add solution D to solution C, react for 24 hours, then centrifuge to collect the precipitate, wash it with water, and finally dry it to obtain a nano-sustained release fertilizer and pesticide with a polydopamine coating.

[0061] Example 7

[0062] (1) Take 0.1 g of zinc acetate, 0.5 g of thiabendazole, 0.1 g of urea, and 0.2 g of ammonium phosphate and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonicate for 5 minutes to dissolve them fully to obtain solution A; dissolve 0.3 g of imidazole-2-carbaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; under the conditions of 25 °C, 300 rpm, and 4 mL / min, add solution B to solution A. After adding, continue stirring for 30 minutes, centrifuge to collect the resulting mixture, and wash it three times with methanol. Finally, dry it to obtain a zinc-based nanocarrier encapsulating fertilizer and pesticide, labeled as LJ-ZIF-90.

[0063] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Under magnetic stirring, add the hydrogen peroxide solution thereto and react for 24 hours. Centrifuge to collect the product, wash it with water, and finally dry it to obtain carboxylated LJ-ZIF-90;

[0064] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; under the condition of stirring at 400 rpm, add solution D to solution C, react for 24 hours, then centrifuge to collect the precipitate, wash it with water, and finally dry it to obtain a nano-sustained release fertilizer and pesticide with a polydopamine coating.

[0065] Example 8

[0066] (1) Take 0.2 g of zinc acetate, 0.5 g of tebuconazole, 0.15 g of urea and 0.15 g of potassium chloride and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to fully dissolve to obtain solution A; dissolve 0.3 g of imidazole-2-carbaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 40 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry to obtain a zinc-based nanocarrier with internal wrapped medicine and fertilizer, labeled as LJ-ZIF-90.

[0067] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water. Add the hydrogen peroxide solution thereto under magnetic stirring and react for 24 hours. Centrifuge to collect the product and wash it with water. Finally, dry to obtain carboxylated LJ-ZIF-90;

[0068] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.15 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; add solution D to solution C under the condition of stirring at 400 rpm. After reacting for 24 hours, centrifuge to collect the precipitate and wash it with water. Finally, dry to obtain a nano-sustained release medicine and fertilizer with a polydopamine coating.

[0069] Example 9

[0070] (1) Take 0.2 g of zinc acetate, 0.5 g of difenoconazole, 0.2 g of urea and 0.1 g of superphosphate and add them to 20 mL of N,N-dimethylformamide solution. Ultrasonic for 5 minutes to fully dissolve to obtain solution A; dissolve 0.3 g of imidazole-2-carbaldehyde in 20 mL of N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under the conditions of 25 °C, 300 rpm and 4 mL / min. After adding, continue to stir for 30 minutes, centrifuge to collect the obtained mixture, and wash it three times with methanol. Finally, dry to obtain a zinc-based nanocarrier with internal wrapped medicine and fertilizer, labeled as LJ-ZIF-90.

[0071] (2) Dissolve 0.41 mmol of hydrogen peroxide in 20 mL of distilled water to obtain a hydrogen peroxide solution; take 0.1 g of LJ-ZIF-90 and disperse it in 30 mL of water, and add the hydrogen peroxide solution thereto under magnetic stirring. React for 24 hours, centrifuge to collect the product, wash it with water, and finally dry it to obtain carboxylated LJ-ZIF-90;

[0072] (3) Disperse 0.6 g of carboxylated LJ-ZIF-90 in 50 mL of water, add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride thereto, and activate for 1 hour to obtain solution C; dissolve 0.30 g of dopamine hydrochloride and 0.36 g of N-hydroxysuccinimide in 30 mL of water until completely dissolved to obtain solution D; add solution D to solution C under stirring at 400 rpm, react for 24 hours, then centrifuge to collect the precipitate, wash it with water, and finally dry it to obtain the nano-sustained release fertilizer and pesticide with a polydopamine coating.

[0073] In order to further prove the beneficial effects of the present invention for better understanding of the present invention, the following comparative examples and test examples further clarify the technical features disclosed in the present invention, but it should not be construed as a limitation to the present invention. For other improvements made by those skilled in the art based on the above-mentioned inventive content without creative work, they are also considered to fall within the protection scope of the present invention.

[0074] Comparative Example 1

[0075] The zinc-based nano-carrier LJ-ZIF-90 for encapsulating the fertilizer and pesticide is not coated, and other steps are the same as those in Example 1.

[0076] Comparative Example 2

[0077] The zinc-based nano-carrier LJ-ZIF-90 for encapsulating the fertilizer and pesticide is not coated, and other steps are the same as those in Example 3.

[0078] Comparative Example 3

[0079] The zinc-based nano-carrier LJ-ZIF-90 for encapsulating the fertilizer and pesticide is not coated, and other steps are the same as those in Example 5.

[0080] Put 20 g of the samples of Examples 1-6 and Comparative Examples 1-3 into a dialysis bag (with a molecular weight cut-off of 10,000 g / mol), seal it with a rope and place it in a 1 L beaker containing 400 mL of deionized water. Take samples at preset times (1 d, 5 d, 10 d, 20 d, 40 d, 60 d, 80 d, 100 d, and 120 d), use high performance liquid chromatography to detect the pesticide content of the samples, and statistically analyze the cumulative release rate of the pesticide in water of the nano-sustained release fertilizer and pesticide prepared in Examples 1-9 and Comparative Examples 1-3.

[0081] Table 1 Pesticide cumulative release rates of nano-sustained release fertilizer-pesticides prepared in different examples

[0082]

[0083]

[0084] From the results in Table 1, we can see that the cumulative release rates of pesticides in Examples 1-9 and Comparative Examples 1-3 all increase with the prolongation of time. The overall cumulative release rates of pesticides in Examples 1-9 are lower than those in Comparative Examples 1-3. The cumulative release rates of pesticides in Comparative Examples 1-3 are close to 100% at 120 d, while the pesticides in Examples 1-9 only release about 75% - 85% of the total amount. This may be because the nano-sustained release fertilizer-pesticides in Comparative Examples 1-3 are not coated with polydopamine, resulting in a relatively fast release rate of pesticides and affecting the sustained release effect.

[0085] In addition, there are certain differences in the cumulative release rates of pesticides among different examples. This may be due to the different interactions between different pesticides and zinc-based nano-carriers and the influence of different reaction conditions on the particle size of zinc-based nano-carriers. According to relevant literature reports, the host-guest interactions between pesticides and metal-organic frameworks involve coordination bonds, hydrogen bonds, electrostatic interactions, π-π interactions and other special effects (e.g., hydrophobic effects and pore filling). Sun et al. found that there are coordination bonds and electrostatic interactions between tebuconazole and zinc-based metal-organic frameworks. In the report of Ma et al., there is a coordination bond between pyraclostrobin and zirconium-based metal-organic frameworks. In addition, Yang et al. reported that an increase in reaction temperature leads to a significant increase in the particle size of ZIF-90-CD, and with the increase in the proportion of β-CD-NH2, the morphology of ZIF-90-CD becomes rougher and obvious agglomeration occurs.

[0086] The above results show that the nano-sustained release fertilizer-pesticides with polydopamine coatings prepared in the examples all have good sustained release effects, can continuously release pesticides for a long time, and effectively extend the drug efficacy time.

[0087] Based on Figure 1 and Figure 2 the results of scanning electron microscopy, it can be seen that the prepared zinc-based nano-carrier ZIF-90 has a crystal structure, is a dodecahedron, and the surface is relatively smooth. While the zinc-based nano-carrier ZIF-90 with a polydopamine coating shows a sub-spherical shape with a rough surface, indicating that the reaction between polydopamine and the zinc-based nano-carrier ZIF-90 is successful.

[0088] The particle size analysis of the above scanning electron microscope images was carried out using Nano Measurer particle size measurement software. The results showed that the average particle size of the prepared zinc-based nanocarrier ZIF-90 was about 120 nm, while after the polydopamine coating, the average particle size increased to about 180 nm, which was consistent with the scanning electron microscope results we observed previously.

[0089] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A nano-sustained release medicine fertilizer with a polydopamine coating, characterized in that, The nano-sustained release medicine fertilizer uses ZIF-90 as a carrier, with the medicine fertilizer wrapped inside the carrier and polydopamine coated outside the carrier; moreover, the nano-sustained release medicine fertilizer, by mass percentage, comprises the following components: 45-60wt% zinc-based nano-carrier ZIF-90, 15-30wt% medicine fertilizer, and 5-15wt% polydopamine; The coating of polydopamine outside the carrier is synthesized by using a coupling agent through the cross-linking reaction of carboxyl and amino groups. The specific steps are as follows: Disperse ZIF-90 wrapped with the medicine fertilizer in water, add hydrogen peroxide, react, then centrifuge and wash to obtain the carboxylated carrier ZIF-90 wrapped with the medicine fertilizer; add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to the aqueous solution of the carboxylated zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer to obtain solution C, activate for 1 hour, and then add the aqueous solution of dopamine hydrochloride containing N-hydroxysuccinimide to solution C. After the mixed solution reacts under stirring, centrifuge, wash, and dry to obtain the nano-sustained release medicine fertilizer with a polydopamine coating; The medicine fertilizer is composed of a bactericide and a fertilizer in a mass ratio of 5:3; the bactericide is one or a combination of thiram, tebuconazole, and difenoconazole, and the fertilizer is one or a combination of urea, ammonium bicarbonate, potassium chloride, ammonium chloride, nitrophosphate potassium fertilizer, superphosphate, and ammonium phosphate.

2. A preparation method of the nano-sustained release medicated fertilizer with a polydopamine coating as described in claim 1, characterized in that, The method specifically comprises the following steps: 1) The zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer is prepared by a simple one-pot method: Take zinc acetate and the medicine fertilizer and add them to an N,N-dimethylformamide solution to obtain solution A; dissolve imidazole-2-carboxaldehyde in an N,N-dimethylformamide solution to obtain solution B; add solution B to solution A under stirring, react, then centrifuge to collect the obtained mixture, wash it three times with methanol, and finally dry to obtain the zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer inside; 2) The coating of polydopamine outside the carrier is synthesized by using a coupling agent through the cross-linking reaction of carboxyl and amino groups: Disperse the zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer prepared in step 1) in water, add hydrogen peroxide, react, then centrifuge and wash to obtain the carboxylated zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer; add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to the aqueous solution of the carboxylated zinc-based nano-carrier ZIF-90 wrapped with the medicine fertilizer to obtain solution C, activate for 1 hour, and then add the aqueous solution of dopamine hydrochloride containing N-hydroxysuccinimide to solution C. After the mixed solution reacts under stirring, centrifuge, wash, and dry to obtain the nano-sustained release medicine fertilizer with a polydopamine coating.

3. The preparation method of the nano-sustained release pharmaceutical fertilizer with a polydopamine coating according to claim 2, characterized in that, In step 1), the ratio of zinc acetate to imidazole-2-carboxaldehyde added is 1:1~1:3 (w / w); the volume ratio of solution A to B is 1:

1.

4. The preparation method of the nano-sustained release pharmaceutical fertilizer with a polydopamine coating according to claim 2 or 3, characterized in that, In step 1), the reaction temperature is 20°C~60°C, the rotation speed is 300 rpm, and the addition speed is 4 mL / min.

5. The preparation method of the nano-sustained release pharmaceutical fertilizer with a polydopamine coating according to claim 2, characterized in that, In step 2), the molar concentration of hydrogen peroxide is 20.5 mmol / L, the mass ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to N-hydroxysuccinimide is 5:3, and the mass ratio of dopamine to the carboxylated zinc-based nanocarrier ZIF-90 encapsulating the drug fertilizer is 1:4 to 2:

1.

6. The preparation method of the nano-sustained release pharmaceutical fertilizer with a polydopamine coating according to claim 2 or 5, characterized in that, In step 2), the reaction temperature is room temperature, the reaction time for adding hydrogen peroxide is 1 hour, and the reaction time for the mixed solution is 24 hours.

7. The preparation method of the nano-sustained release pharmaceutical fertilizer with a polydopamine coating according to claim 2, wherein In step 2), the volume ratio of solution C to the aqueous dopamine hydrochloride solution containing N-hydroxysuccinimide is 5:3.

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